As is well known to those skilled-in-the-art, polyolefins such as polyisobutylene (PIB) may be functionalized with difficulty because of the hydrocarbon-like non-reactivity toward common chemical reagents. It has heretofore been found to be extremely difficult to impart amine functionality to such polymers.
The prior art teaches primarily one method for preparation of polymers containing several primary amine groups attached directly to the polymer. This method consists of a three step process involving (1) chlorination of an olefin-containing polymer followed by (2) dehydrohalogenation and (3) reaction of the resultant chlorinated polymer with ammonia and a sufficient amount of base to convert the product chloride to the free amine. This process leads to products containing more than one amine group per polymer molecule. This occurs because it is virtually impossible to react the polymer with chlorine and obtain chlorination only at the olefinic center of polyisobutylene. Chlorination also occurs on the polymer backbone, producing products with more than two chlorine atoms per polymer molecule. When converted to the primary amine these multichlorinated polymers give products containing more than one amine group per polymer molecule.
It is an object of this invention to provide a novel process for improving the dispersancy of lubricating oils. It is another object of this invention to provide a process for functionalizing polymers such as polyisobutylene. Other objects will be apparent to those skilled-in-the-art.